Cranial repair surgery is a kind of routine surgery in neurosurgery clinic, which is aimed at repairing cranial defects caused by various reasons, remodeling the complete and closed cranial cavity, compensating for the mechanical safety and protection of brain tissues, restoring the stable intracranial environment, solving the anomalies such as insufficient cerebral blood supply and cerebrospinal fluid circulation, and at the same time trying to restore the patient’s original appearance as much as possible. Although cranial repair surgery is a routine surgery, which can be carried out by neurosurgery departments of larger hospitals around the world, it is not easy to do it properly, especially when encountering some special and thorny problems, which require senior and experienced neurosurgeons to solve them properly. For example, some patients ask what it means to do a hydrocapsule for cranial repair with high scalp tension. This is indeed a problem that may be encountered in cranial repair surgery, and we will explain it specifically below: What is the need for an aquaplasty? There are many reasons why a patient may have a cranial defect, either due to trauma, or due to a surgical procedure, or a partial resection of the skull itself. The anterior process may cause partial defect of the scalp. If the skull is directly repaired and artificial bone flap material is placed, there may not be enough skin of the scalp, which cannot be docked together and cannot be sutured; or it can barely be sutured, but the tension of the scalp will be very high after the suture, and there is a strong sense of tightness, which may affect the postoperative healing, and even the incision collapses. Then in this case, you can pre-bury water bladder under the skin for skin expansion. There is also a situation where the local scalp is very thin due to various reasons, and there may be skin breakage and loss during the surgery, which should be assessed scientifically and if necessary, scalp hydrocapsule dilatation should be considered in the early stage, so that the scalp area is enlarged and ready to be used. What is the purpose of hydrocapsulorhexis? The purpose of the hydrocapsule is to expand the skin, through the expansion of the hydrocapsule, the scalp can be extended and grow, the skin area can be enlarged, in order to repair the defect of the scalp, so as to cover the skull, and after the skull is repaired and reset, the skin can be sutured in the right position without excessive tension and tightness, so as to achieve a better restoration effect. Another effect is that it may be possible to repair to some extent the scalp scarring that occurs in the preexisting period and achieve a better appearance. What exactly is the procedure for hydrocapsular scalp expansion? The specifics of a bladder augmentation procedure are not really complicated. It involves cutting the scalp at a suitable location, placing an empty, flat bladder under the skin, usually under the capitellum, and then suturing the skin. After the skin incision has healed and grown strong, an external device is used to inject water into the capsule through a skin puncture in small increments. It is generally recommended to inject water twice a week, with about 10 ml of water each time. In this way, through the gradual expansion of the water capsule, the scalp can be expanded and grown for restoration. Generally about three months can achieve a more ideal effect of scalp expansion.